Following are suggested specifications for risers, treads, width, and headroom. These specs will help you build a safe, comfortable set of stairs. These do not universally dictate all stair measurements; rather, be sure to check with local agencies about building codes that apply to your structure. Many communities adopt the International Building Code wholesale, while others make modifications.
Are We On the Same Page? Common Stair Terms:
- The stringer is the entire "saw-toothed" member upon which risers and tread rest. You'll need two per staircase.
- A riser is the vertical measurement of each stair. Risers can either be enclosed or left open.
- The tread is the horizontal section of each stair. This is the part you step on.
- When we say width, we are referring to the measurement of risers and treads from side to side, as if you were walking up or down the stairs.
- Headroom is one dimension that often gets ignored. Imagine drawing a sloped line along the noses of each tread (see the dotted line on the accompanying image). The vertical measurement above this sloped line is the headroom.
Stair Riser Height7 3/4 inches, maximum.
Stair Tread Length10 inches, minimum.
Stair Width36 inches, minimum. This measurement does not include handrails.
Stair Headroom6 feet, 8 inches, minimum.
Railings are almost always required on stairs. Check out our separate page about stairway code for handrails and guards.
These suggested measurements are for straight interior stairs. For more information on building codes, see the links below.